Block laying Paper 2 WASSCE (SC), 2016

Question 3

3. (a)List four types of Portland cement.

     (b)Sketch each of the following types of foundation:
(i)pad;
(ii) raft.

     (c)State two advantages of steel formwork over timber formwork.

Observation

Most candidates were able to list four types of Portland cement and sketch pad
and raft foundation.  However, few of them failed to state two advantages of steel
formwork over timber formwork.

The expected response to question 3 is as given below:

3.(a)Types of  Portland cement                  

  1. Ordinary Portland cement.
  2. Rapid-hardening Portland cement / High-early strength cement
  3. Extra-rapid hardening Portland cement.
  4. Super sulphated cement.
  5. Sulphate-resisting Portland cement.
  6. Pozzolanic Portland cement.
  7. Hydrophobic Portland cement/Water-repellant Portland cement.
  8. Blast furnance slag cement/Portland blast furnace cement.
  9. Low heat Portland cement
  10. White Portland cement.
  11. Coloured Portland cement.
  12. Masonry cement.

(c)        Advantages of steel formwork over timber formwork:

  1. it is more durable than timber formwork;
  2. it can be used as many times as possible;
  3. it is not liable to warp;
  4. it gives a smooth surface finish to the concrete;
  5. it is more economical than timber where repetitive work is necessary;
  6. it is easier to erect and remove;
  7. it provides/gives a more precise and accurate shapes and edges.